Yes — Strong Match
cleome (zones 2-11) covers every zone Connecticut contains (6a-7b), so hardiness is not what limits it anywhere in the state.
Cleome in Connecticut — the short answer
Cleome in Connecticut: hardy in zones 2–11, full sun, against a state median of ~207 frost-free days.
- Plant zones
- 2-11
- Manual horticultural correction (source not retained); NC State Extension and Missouri Botanical Garden, with the remaining rows from other published sources or Growable Ground compilation
- Connecticut zones
- 6a-7b
- USDA PHZM 2023
- Frost window
- Mar 31 - Apr 11 – Oct 30 - Nov 3
- NOAA RCC ACIS 1991-2020, 28°F
- Shortest county season
- 191 days
- NOAA Regional Climate Centers ACIS, 1991-2020, county 28°F killing freeze
- Days to maturity
- 80 days
- Growable Ground Plant Database
Plant data: Growable Ground Plant Database, compiled from FAO ECOCROP, USDA PLANTS and university Extension sources — per-field provenance varies and is published with the dataset.
Your yard isn't the whole zone.
Cleome is grown as an annual, so your winter zone isn't the deciding factor — your frost-free window is. A typical Connecticut site runs ~207 frost-free days, but that is a state median, not your yard: slope, trees, and low spots move the last-frost date across a single parcel. Enter your address and we'll score cleome against your land's actual frost dates, sun, and soil.
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Connecticut is not one climate
A single Connecticut answer averages 9 counties whose growing seasons are 48 days apart — from 191 frost-free days in Northwest Hills County to 239 in Greater Bridgeport County. Which end of that your land sits nearer changes what cleome can finish before the first hard freeze.
The middle half of 9 counties runs 202–216 days, with a median of 207 days — a 48-day span end to end.
Measured across 9 Connecticut counties. NOAA Regional Climate Centers ACIS, 1991-2020, county 28°F killing freeze. Quartiles are order statistics — every figure shown is a value a real county recorded, not an interpolation. Your own site sits somewhere inside this range; a parcel report resolves where.
Where in Connecticut Fits Best
Even within Connecticut's zones 6a-7b, county microclimates differ enough to change what thrives. These counties carry the closest zone match for cleome (USDA PHZM 2023):
Zone Comparison
Cleome Needs
- USDA Zones: 2-11
- Sun: Full Sun
- Mature size: 4 ft tall
- Picking window: ~90 days of harvest
- Drought tolerance: High
Connecticut Has
- USDA Zones: 6a-7b
- Last Hard Freeze (28°F): Mar 31 - Apr 11
- First Hard Freeze (28°F): Oct 30 - Nov 3
- Annual Rainfall: 44-52 inches
- Common Soils: Glacial till, Sandy loam, River valley silt
Plant Zone Range (zones 2-11)
Preferred Soil pH
Plant data: Growable Ground Plant Database, compiled from FAO ECOCROP, USDA PLANTS, and university Extension sources — per-field provenance varies and is published with the dataset. State data: USDA ARS PHZM 2023, NOAA Climate Normals, NRCS SSURGO.
When to Plant Cleome in Connecticut
The frost window
Across Connecticut, the last spring hard freeze (28°F) clears between Mar 31 and Apr 11, and the first fall hard freeze lands between Oct 30 and Nov 3 (NOAA Regional Climate Centers ACIS, 1991-2020). Counting from the latest last freeze to the earliest first freeze, that's a 202-day window you can count on — up to 217 days on a mild site in a kind year. That marks the hard freeze, not the last light frost, so tender transplants usually wait another 2-3 weeks.
Frost tenderness
Cleome is frost-tender — FAO ECOCROP puts its killing temperature at 32°F — so set plants out two to three weeks PAST your local last hard freeze, not on it and not on the state's earliest date. The 28°F marker above is when killing freezes stop, not when light frost does. That is the point where cold damages growing tissue, not a winter-survival floor — an established perennial comes through far colder while dormant, which is what its hardiness zone tells you.
When to start the seed
Those dates are when cleome goes out, not when it starts. It is sown under cover about 4 weeks ahead, so counting back from Connecticut's late-side last freeze of Apr 11 is what fixes your sowing date — and a yard that clears frost earlier than the state's late date starts earlier still.
Days to maturity vs. the window
At 80 days to maturity (Growable Ground Plant Database), counting from the last hard freeze it ripens with 122 days to spare even in Connecticut's tightest freeze scenario — room for a later start or a second sowing.
Frost window: NOAA Climate Normals 1991-2020. Plant timing fields: Growable Ground Plant Database — frost-free days from FAO ECOCROP, days to harvest from university Extension production guides, and growing-degree-day and chill-hour minimums that are compilation estimates rather than published figures. Your site's own frost dates can run earlier or later than the state range — a parcel report pins them down.
Growing Season Fit
The zone check says cleome survives winter here. Whether the season is long enough — and warm enough — is a different question.
Days to maturity
Cleome matures in ~80 days (Growable Ground Plant Database). A typical Connecticut site has ~207 frost-free days, so plenty of room for a second succession.
Growing degree days
Cleome needs ~1000 GDD (base 50°F) to ripen. The state median runs ~2664 GDD (from PRISM 1991-2020 climate normals), so Connecticut's typical season clears that easily.
GDD and chill-hour figures are computed from PRISM 1991-2020 monthly climate normals; frost-free days from NOAA Regional Climate Centers ACIS, 1991-2020. Each is the state median across its counties (P25/P75 span the within-state spread). Hardiness-zone range is USDA PHZM 2023.
Soil + Drainage Fit
Cleome likes near-neutral soil (pH 5-7.5). That's the common-ground band across Connecticut's glacial till and sandy loam — a soil test confirms it for your site. It will grow across that whole span, but it does best between pH 5.5 and 7 — worth knowing before you decide whether a Connecticut soil test result is a problem or just a number. Drainage matters: this plant wants well (dry spells). If your Connecticut site is heavier clay or sits in a low spot, raised beds or amendment with compost solve it.
Plant pH requirements: FAO ECOCROP and USDA PLANTS, with the remaining rows from other published sources or Growable Ground compilation. Drainage: FAO ECOCROP, with the remaining rows from other published sources or Growable Ground compilation. Connecticut soil profile from USDA NRCS SSURGO. Site-specific verification: a 30-minute soil test from your local Extension lab.
What Else to Consider for Cleome in Connecticut
Zone compatibility tells you about winter cold survival — but Connecticut growers also need to think about:
Rocky glacial soils require clearing and amendment
Short growing season in northern hills
Deer pressure is high in suburban areas
What to actually do about these — and the constraints that apply to every Connecticut grower, not just cleome — is covered on the Connecticut growing guide.
Timing shifts within Connecticut
Cleome needs about 80 days of frost-free season from planting to harvest. Even Northwest Hills County — Connecticut’s shortest season at 191 frost-free days — clears that by 111 days, so season length isn’t the constraint anywhere in Connecticut. What varies is your own parcel.
County last-freeze dates and frost-free day counts: NOAA Regional Climate Centers ACIS (1991-2020), county 28°F freeze (earlier than the folk 32°F "last frost"). Cleome's 80-day requirement: USDA PLANTS / Growable Ground plant database (days to maturity). A parcel report resolves your address's own frost dates.
Pollinator + Wildlife Value
Cleome draws honeybees, native bees, butterflies, and hummingbirds (high value, Growable Ground Plant Database). Planting it near vegetable beds can lift fruit set on neighboring crops. Outdoors, cleome can only work that bloom inside Connecticut's frost window — roughly 207 days, opening after the last 28°F freeze (Mar 31 - Apr 11) and closing at the first (Oct 30 - Nov 3), per NOAA Regional Climate Centers ACIS, 1991-2020.
Connecticut Cooperative Extension
For Connecticut-specific cultivar recommendations, planting calendars, and pest pressure for cleome, the canonical source is UConn Extension. Their fact sheets carry the local trial data we can't generalize across 50 states.
Is Cleome native to Connecticut?
No — the USDA PLANTS Database lists Cleome as introduced rather than native in the Lower 48, so it is not part of Connecticut's native flora. It grows here as a garden plant; pairing it with a few Connecticut natives keeps local pollinators fed too.
Looking for plants that belong here? The Connecticut growing guide lists USDA-documented natives for the state.
Native-range data: USDA PLANTS Database state-distribution records, accessed 2026-07-01.
Common Questions About Growing Cleome in Connecticut
When can I plant Cleome in Connecticut?
Connecticut's last spring hard freeze (28°F) clears between Mar 31 and Apr 11, and the first fall hard freeze lands between Oct 30 and Nov 3 (NOAA Regional Climate Centers ACIS, 1991-2020). Cleome is frost-tender — its killing temperature is 32°F (FAO ECOCROP — the point where cold damages growing tissue, not a winter-survival floor) — so wait two to three weeks past your site's last hard freeze, when light frost has also stopped, before planting out.
Can Cleome mature before first frost in Connecticut?
Yes — Cleome matures in 80 days (Growable Ground Plant Database), and Connecticut's dependable hard-freeze-free window runs 202 days (NOAA Regional Climate Centers ACIS, 1991-2020), leaving 122 days of margin. Plant once the last hard freeze has passed — two to three weeks later for anything tender — and it ripens ahead of the first fall freeze.
What hardiness zone is Cleome grown in across Connecticut?
Connecticut spans USDA hardiness zones 6a-7b (USDA ARS PHZM 2023). Cleome carries a range of zones 2-11, so the overlap zones are where outdoor growing is most reliable.
How many frost-free days does a typical Connecticut site have?
A typical Connecticut site sees ~207 frost-free days per year (derived from NOAA Regional Climate Centers ACIS, 1991-2020). Cleome should be matched against that window, so check whether your local microclimate runs above or below the state average before settling on a planting date.
Is Cleome native to Connecticut?
No — the USDA PLANTS Database lists Cleome as introduced rather than native in the Lower 48, so it is not part of Connecticut's native flora. It grows here as a garden plant; pairing it with a few Connecticut natives keeps local pollinators fed too.
How should I amend the soil for Cleome in Connecticut?
Cleome prefers pH 5-7.5 and well (dry spells) drainage (FAO ECOCROP). That sits in the common-ground band across Connecticut soils — a 30-minute soil test from a local Extension lab confirms it for your specific site.
Will Cleome actually grow on my specific land in Connecticut?
State-level zone + climate data is a sketch. A Growable Ground parcel report scores cleome against your address's exact soil pH, drainage, sun, and frost-date data drawn from USDA SSURGO, NOAA, and PRISM — not state averages.
Check your specific parcel in Connecticut
State-level data is a sketch. Your Growable Ground report scores cleome against your parcel's exact soil, sun, drainage, and frost data — not zone averages.
Three things about your lot that Connecticut cleome averages can't show:
We read public map data around Connecticut — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Connecticut cleome average
Explore More
Growing guides for cleome
Explore Connecticut county by county
Connecticut carries 9 counties with their own USDA zone — a sample of the growing pages for cleome there:
Where else cleome grows
Cleome's zone band crosses state lines — these are the states closest to Connecticut in winter climate where it also has a page, plus the far ends of its range. Each one re-answers the question with that state's own record.
More to grow in Connecticut
Connecticut has a growing page for 893 plants — a rotating sample of the rest of the shelf.
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